Electric dry shaver wherein the cutter shaft is mounted in a rubberlike material



Y Z5 A 20d Sept. 2l, 1965 l. JEPsoN 3,206,850

ELEC C DRY AVER WHEREIN THE CUTT SHAFT MOUNT IN A RUBBERLIKE MATE L 2Sheets--Sheet 1 Filed Nov. 13. 1962 54 '5 e; zo? 4947, 27 20 ATTORNEYSept. 21, 1965 l. JEPsoN 3,206,850

ELECTRIC DRY SHAVER WHEREIN THE CUTTER SHAFT IS MOUNTED IN A RUBBERLIKEMATERIAL Filed Nov. 13, 1962 2 Sheets-Sheet 2 5l INVENTOR 27mg@ l?, ChekATTORNEY ||\""l im, 204 BY WAK .JE-Pfam United States Patent ELECTRICDRY SHAVER WHEREIN THE CUT- TER SHAFT IS MOUNTED IN A RUBBER- LIKEMATERIAL Ivar Jepson, Oak Park, Ill., assignor to Sunbeam Corporation,Chicago, Ill., a corporation of Illinois Filed Nov. 13, 1962, Ser. No.237,239 4 Claims. '(Cl. 30-43.9)

The present invention relates to apparatus for removing beards or facehair as well as for removing hair from the arms, legs and other portionsof the human body, and is generally referred to as an electric dryshaver. More particularly, the present invention is in the nature of animprovement over the electric dry shaver disclosed and claimed incopending Jepson and Schuessler application Serial No. 109,551, tiledMay 12, 1961, and assigned to the same assignee as the presentapplication.

The electric dry shaver disclosed in the above-mentioned copendingJepson and Schuessler application is one in which the hair to beremoved, such as the beard, enters the cutting area through a network ofsmall holes in a curved perforated comb. An oscillating cuttercomprising a plurality of spaced parallel blades travels back and forthacross the comb at high speed and is shrown by centrifugal force againstthe inside surface of the comb, thus providing a very satisfactorycutting action with the comb. The cutter blades float in a cutter headand shaft assembly that is also oscillated by a powerful electric motorwith the cutter blades oscillating on the order of 8,500 cycles perminute. In the above-mentioned copending application, the oscillatingshaft for the cutting blades is supported in spaced bearings and themanufacturing cost of such a shaver is substantial due to therequirement of bearings which must be carefully aligned and which musteither be lubricated or comprise bearings of the self-lubricatingnature. It would be desirable to provide an arrangement in which thebearings for the oscillating cutter shaft could be completelyeliminated, thereby eliminating the cost of such bearings, the morecomplicated assembly thereof and all misalignment problems with respectthereto.

It will be appreciated that in a shaver in which the cutting blades areoscillated, at each end of the stroke the blades must come to a stop andthen movement in the opposite direction must take place. This means thatat each end of the stroke it is necessary to overcome the inertia 0f themoving parts which are momentarily in a stationary condition. It wouldbe desirable to provide an arrangement wherein it is unnecessary toovercome the inertia of the blade assembly at the ends of the oscillating strokes to move it in the opposite direction, but in some manner toprovide an energy storage arrangement whereby energy stored during aportion of the operating stroke is released to overcome this inertia forthe return stroke. Moreover, it would also be desirable to provide somesort of resilient stop whereby the blade assembly which stopsmomentarily at each end of the stroke is cushioned to such stop.

In oscillating shavers of the type disclosed in the abovementionedcopending Jepson and Schuessler application, to insure the .properbalance of the movable portions of the cutter head assembly, it wasnecessary to provide counterbalancing means commonly in the form of acounterweight of some sort which, of course, increased the mass of theoscillating structure, and, secondly, produced a space problem in makingprovision for such counterbalancing means which is usually in the formof a Weight of some sort. It would be desirable to provide anarrangement which permits one to eliminate such counterbalancing means.

ICE

In the dry shaver of the oscillating cutter type, particularly oneemploying a plurality of blades, such as disclosed in the copendingJepson and Schuessler application, a very powerful motor is required tooscillate the cutters and supporting mechanism therefor at the highspeeds desired for proper cutting operation. It would be desirable toprovide an improved power system whereby with the same comb structureand the same cutter structure a power reduction of between twenty andfifty percent could be obtained.

Accordingly, it is an object of the present invention to provide a newand improved electric dry shaver.

It is another object of the present invention to provide a dry shaver ofthe type employing an oscillating cutting mechanism wherein theconventional bearings for the oscillating shaft may be completelyeliminated with the consequent elimination of the bearing misalignmentproblem.

It is a further object of the present invention to provide a new andimproved dry shaver whereby the same cutting action is obtained with areduction in power input of between twenty and fifty percent.

It is another object of the present invention to provide a cuttermechanism for an electric dry shaver in which the lubrication problem iscompletely eliminated.

Still another object of the present invention resides in an electric dryshaver having a rotating motor feeding power to an oscillating cuttermechanism wherein the requirement to overcome the inertia of the cutterblade assembly at each end of its stroke when the direction of motion ischanged is eliminated and instead stored energy is utilized to act as acushioned ystop and, moreover, overcome the inertia with respect tomovement in the opposite direction.

It is a still further object of the present invention to provide anoscillating cutter mechanism for an electric dry shaver in which thecounterbalancing problem is completely eliminated.

It is a further object of the present invention to provide an improvedelectric dry shaver which will give years of trouble-free service andwhich can be manufactured and assembled at a greatly reduced cost.

Further objects and advantages of the present invention will becomeapparent as the following description proceeds and the features ofnovelty which characterize the invention will be pointed out withparticularity in the claims annexed to and forming a part of thisspecification.

For a better understanding of the present invention, reference may behad to the accompanying drawings in which:

FIG. 1 is a fragmentary, longitudinal sectional view taken along a planepassing substantially through the axes of the shafts of the rotatingmotor and oscillating cutter of an electric dry shaver embodying thepresent invention;

FIG. 2 is a sectional view taken on line 2-2 of FIG. 1 assuming thatFIG. 1 shows the complete structure;

FIG. 3 is a sectional view taken on line 3-3 of FIG. 1 again assumingthat FIG. 1 shows the complete structure;

FIG. 4 is a sectional View taken on line 4-4 of FIG. 1 assuming thatFIG. 1 shows the complete structure;

FIG. 5 is an enlarged fragmentary sectional view of the supporting meansfor the oscillating shaft of the cutter mechanism; and

FIG. 6 is an exploded perspective view of the oscillating bladesuporting mechanism and the means for supporting the same in theelectric dry shaver of the present invention.

Briey, the present invention is concerned with an improved oscillatingcutter assembly for an electric dry shaver wherein the bearings for theoscillating cutter shaft are completely eliminated and instead the endsof this cutter shaft are resiliently mounted. In the preferredembodiment, the ends of the cutter shaft are secured to blocks of arubberlike material whereby beanings and lubrication problems arecompletely eliminated, the alignment problem is eliminated and a greatlyreduced power requirement is obtained since energy stored in theresilient support is fed back into the power system at each end of theoscillating stroke, thereby overcoming the inertia inherent in a devicewhich must stop and reverse its direction of movement. By eliminatingthe bearings a sound reduction of the order of twenty-five to thirtypercent results. The resilient means for mounting the oscillating shaftis preferably chosen to have a natural frequency of Vibration whichapproaches the frequency of oscillation of the cutter mechanism.Moreover, the resilient support means must be such as to be unaffectedby the various shaving lotions that might be employed and unaffected byozone which is produced with a commutator-type motor. Due to theresonant condition and the fact that energy is stored in the resilientsupports and is released to overcome the inertia of the oscillatingshaft and blade assembly at each end of the stroke, a substantialreduction in power requirements results. This reduction is betweentwenty and ifty percent. Moreover, the resilient mounting means for theoscillating shaft effectively provides a stop to cushion the oscillatingcutters at each end of the stroke. Moreover, it is unnecessary tocounterbalance the cutter assembly with this type of arrangement.

Referring now to the drawings, the electric dry shaver embodying thepresent invention is generally designated by the reference numeral 10.Since the present invention is primarily concerned with the oscillatingcutter mechanism and the power train and power supplying mechanismconnected therewith, only fragmentary views of the entire shaver areshown. lt should be understood, however, that this shaver mightotherwise be very similar to that disclosed in the above-mentionedJepson and Schuessler application. Moreover, the general construction ofthe shaver may be very similar to that disclosed and claimed in acopending application Serial No. 322,- 795, Jepson, Schuessler, Jacksonand Jensen, filed November 12, 1963, also assigned to the same assigneeas the instant application. Essentially, the shaver cornprises a cuttingmechanism generally designated at 11 comprising a plurality of cuttingblades 12, only one of which is Visible in the drawings, coacting with acomb or stationary cutting member 13. The comb and cutting mechanism areassociated with a suitable casing comprising three parts 14, and 16, thecomb 13 preferably comprising a substantial portion of the surface ofthe casing. The particular construction of the casing portions 14, 15and 16 forms no part of the present invention but may be very similar tothe corresponding parts disclosed in the copending Jepson and Schuesslerapplication referred to above. Housed within the casing, comprisingportions 14, 15 and 16, is a suitable electric motor, generallydesignated at 18, which is adapted to be connected by suitable drivingmeans, generally designated at 19, with the cutter mechanism 11 in orderto cause oscillation of this cutter mechanism at a speed of the order of8,500 cycles per minute.

As is fully disclosed in the aforesaid Jepson et al. copendingapplications, the casing for the electric shaver is of boxlikeconfiguration so that it may readily be held in the hand of the user andno further discussion of this feature is included herein. Moreover, thecasing is manufactured in three sections, as described in the aforesaidcopending applications, in order to facilitate assembly of the electricdry shaver 10. Actually the casing section 14 preferably molded from asuitable plastic material is a rectangular cup-shaped member having anopen top and a closed bottom (not shown). The casing sections 15 and 16are effectively end caps which may be molded of a suitable plasticmaterial in the same manner as the casing section 14. Actually, in anembodiment built in accordance with the present invention, the end cap15 was molded of a plastic material while the end cap 16 was made as adie casting of a suitable metal.

In accordance with the arrangement disclosed and claimed in Jepson etal. application Serial No. 322,795 referred to above, the shaver 10includes a molded insulating support or chassis 20 to which the cutterassembly 11 and the motor 18 are mounted in the manner describedhereinafter. When the member or chasis 20 is associated with the shaver10, it actually divides the shaver casing into two chambers-a motorchamber 21 disposed beneath the chassis 20, as viewed in FIG. l of thedrawings, and a cutting chamber 22 disposed above the member 20. Theunderside of the chasis member 20 is provided with a pair of downwardlydirected spaced projecting portions 20a and 2Gb terminating in sphericalsurfaces for retaining spherical motor bearings 23 and 24, respectively.The portions 20a and 201; are provided with recesses 25 and 26,respectively, for receiving suitable oil wicks 27 preferably saturatedwith a suitable lubricant.

Between the projecting portions 20a and 20h of the chassis 20 is aportion defining a recess 28 for accommodating the armature 29 of themotor 18 which is supported on a shaft 30 journalled in the bearings 23and 24. The bearings 23 and 24 are secured within the spherical recessesdefined at the lower end of the projections 20a and 20h of the chassis20 by suitable bearing retainers 32 and 33, respectively, which therebyhold the motor 29 in assembled relationship with the chassis 20. Thebearing retainer 32, which might be termed the commutator end bearingretainer, is suitably secured to the chassis 20 by screws or otherfastening means 41 which actually extend through the chassis into tappedopenings in the end cap 15, thereby simultaneously securing the bearingretainer 32 and the end cap 15 in assembled relationship with thechassis 20. The bearing retainer 33, on the other hand, which might betermed the crank end bearing retainer, is secured to the chassis 20 bysuitable screws or fastening means 36, best shown in FIGS. 2 and 3 ofthe drawings.

The chassis 20 is further provided with a downwardly projecting supportmember 20c only a portion of which is shown in the drawings forsupporting suitable terminal pins whereby electrical connection may bemade for energizing the electric motor of the present invention. If itis desired to provide a separate switch built into the shaver housing asis shown in the above-mentioned Jepson and Schuessler application,Serial No. 109,551, then the projection 20c may support a suitableswitch supporting member which, in turn, may also support the electricalterminals.

The particular construction of the motor 18 forms no part of the presentinvention, but as disclosed in Jepson Patent 2,688,184 includes acommutator 39 With which is associated a brush terminal assembly 40(FIG. l) suitably secured to the chassis 20 by fastening means, notshown.

For the purpose of converting rotary motion of the motor shaft 30 tooscillating motion of the cutter assembly 11, the end of the motor shaft30 adjacent crank end bearing retainer 33 is provided with suitablecombined crank and counterweight means including a counterweight 43 anda crank pin 44. The crank pin 44 is connected to one end of a connectingrod 45 preferably formed of nylon which extends through an opening 46(FIGS. 1, 2 and 6) in the chassis 20. The motor 18 includes theconventional field structure very similar to that shown in theabove-mentioned Jepson patent. Only the laminations 47 are visible inFIGS. l and 2 of the drawings. These laminations include a portionsurrounding the armature 29, as is well understood by those skilled inthe art, and a field winding, not shown, surrounds a portion of theselaminations. As is disclosed in the copending Jepson et al. application,Serial No. 322,795, the field structure including the laminations 47 issupported from chassis 20 by a pair of bail clamps 48, which in turn aresupported by a molded bail hanger 49 resting on the top of chassis 20.Actually, the chassis 20 is provided with suitable openings throughwhich the bail clamps 48 may extend to engage the bail hanger 49.

To support the chassis 2t) and the motor and cutting mechanism mountedthereon with respect to the casing, the chassis 20 is provided with aperipheral laterally projecting flange 20d which is adapted to engage acooperating ledge 50 defined around the periphery of the open end of thecup-shaped casing portion 14, as best shown in FIGS. 1, 2, 3 and 4 ofthe drawings. It will be appreciated that the subassembly comprising thechassis Ztl, to which have been secured the armattue and field structuredescribed heretofore of motor 18, as well as the cutting mechanism 11 tobe described and the end caps 15 and 16, is then associated with thecup-shaped casing section 14 by inserting the depending portion thereofinto this casing section, whereupon the latter can then be secured tosuitable means supported by the bail clamps 4S to complete the assembly.

In order to support suitable comb locks, not shown, for retaining thecomb 13 in position, as disclosed in the above-mentioned I epson patent,there is provided a comb lock spring 51 (FIGS. 1 and 6) which isinterposed between the chassis 2t) and the bail hanger 49. If desired,the chassis 20 may be provided with integral projections, such as Ztie(FIG. l) for temporarily retaining the comb lock spring 51 in positionduring assembly. It will be understood that the bail clamps 4S clamp thecomb lock spring between chassis 20 and bail hanger 49 upon finalassembly of all parts.

As in the above-mentioned copending Jepson and Schuessler application,Serial No. 109,551, the cutter assembly 11 includes a cutter shaft 52disposed in spaced parallel relationship with the motor shaft 30. lnorder resiliently to support a plurality of cutter blades, such as 12,for oscillation with the cutter shaft 52, the latter is provided with aplurality of upwardly extending supports 53a, 53h, 53e and 53d which maybe identical with those disclosed in the above-mentioned copendingJepson and Schuessler application. These supports are of triangularshape and are rigidly secured to the cutter shaft 52. They are providedwith suitable slots to receive the cutter blades 12 and suitable bladesprings 61 therein in the same manner disclosed in the Jepson andSchuessler application referred to above. The details of a particularembodiment illustrating one arrangement of the supports is best .shownin FIG. 6 of the drawings.

In accordance with the present invention, conventional bearings for theoscillating cutter shaft 52 have been completely eliminated and insteadopposite ends of this cutter shaft are knurled as indicated at 52a and5217 (FIG. 5), and a pair of rectangular blocks of a resilient material,preferably a neoprene rubber, designated at 54 and 55 are securelybonded to the knurled portions 52a and 52h of shaft 52.

In order to support the oscillating shaft 52, the chassis 20 is providedwith a pair of upwardly projecting support portions 207c and 20g, eachof which is provided with an upwardly directed V-shaped notch 57 and 58,respectively. These V-shaped notches 57 and 58 are respectively adaptedto receive therein the resilient supports 54 and 55 bonded to shaft 52.To clamp the resilient supports 54 and 55 into notches 57 and 55, theend caps 15 and 16 are provided with cooperating V-shaped notches 59 and60, respectively. Thus, end cap is provided with a projection 15a havingarcuately arranged comb supporting surfaces 15b. Moreover thisprojection 15a is provided with the downwardly directed V-notch 59cooperating with the V-notch 57 in the support 20] so as to clamp theresilient block of neoprene rubber 54 into fixed position relative tochassis 20. Similarly, the end cap 16 is provided with a projection 16ahaving a downwardly directed V-notch 60 whereby the resilient support 55may be clamped into position within the cooperating notches 58 and 60.End cap 16 is also provided with arcuately arranged comb supportingsurfaces 16h (FIG. 3). As was described earlier, screws such as 41(FIGS. 1 and 4) clamp the end cap 15 to the chassis 20 simultaneouslyholding the commutator end bearing retainer 32 and, hence, the bearing23 in position and also clamping the resilient support 54 in fixedposition. Similarly, a pair of screws 62 (FIG. 2) are provided forclamping the end cap 16 to the chassis 20 and simultaneously clampingthe resilient support 55 for the oscillating shaft 52 in position.

The driving means 19 includes a combined crank and counterweightcomprising crank pin 63 and counterweight 64 secured to the end ofoscillating shaft 52 adjacent the crank end of motor shaft 30, theshafts 30 and 52 being substantially coextensive. The crank pin 63 isadapted to be connected to the other end of connecting rod 45, thisconnecting rod passing through opening 46 in chassis 20.

In an electric shaver built in accordance with the present invention,the resilient blocks 54 and 55 had a natural frequency of vibration ofbetween 5500 and 7500 cycles per minute. These blocks were made ofneoprene rubber and had a Durometer hardness of between 40 and 45. Thismaterial was resistant to ozone gas, had a tensile breaking stress of atleast 3500 pounds and met many tests with respect to resiliency,compression set, elongation, and the like. The material should beresilient enough so as not excessively to increase the starting torqueand yet should have sufficient hardness to store a substantial amount ofenergy when the blocks are stressed in torsion. With this arrangementefficiency was increased in excess of twenty percent and the cost ofmanufacture and assembly was greatly reduced by the elimination ofbearings, by the elimination of bearing and shaft burnishing previouslyrequired by the elimination of shaft bearing alignment problems, as wellas by completely obviating any requirement for lubrication. Furthermore,it was unnecessary to counterbalance the cutter shaft assembly asheretofore required, thus further reducing the manufacturing cost.

It should be understood that instead of utilizing resilient blocks ofrubberlike material for storing energy other resilient means, such asresilient springs or the like, may be employed for this purpose inconnection with a rotary motor which supplies energy through a drivingmeans to an oscillating mechanism. An arrangement for storing energy inconnection with an oscillating cutter shaft utilizing compressionsprings for this purpose is shown in copending Jepson and Kukulskiapplication Serial No. 246,488, tiled December 21, 1962, and assigned tothe same assignee as the instant application. It should be understoodthat such resilient spring means might be employed instead of the blocks54 and 55 or in addition thereto for storing energy to be fed back intothe power train at each end of the oscillating stroke.

In view of the detailed description set forth above, the operation ofthe electric shaver of the present invention will readily be understoodby those skilled in the art. As the electric motor 18 rotates, it causesoscillation of the cutter shaft 52 stressing the resilient blocks 54 and55 in torsion as the oscillating cutter mechanism moves from one end ofits stroke to the other. Energy is stored in these resilient blocks asthe cutting mechanism moves to the end of its stroke. The blocks cushionthe mechanism to a stop and the stored energy in the resilient blocksthen overcomes the inertia of the moving parts and gives up this energyin producing movement in the opposite direction. Consequently, a smallermotor is required 7 and much more etlicient utilization of the output ofthe motor 1S is accomplished.

From the above description it will be apparent that without the energystorage means of the present invention, very high bearing pressures willresult such as at the crank pins 44 and 63, etc., each time theoscillating cutter mechanism slows down or accelerates at the ends ofeach stroke. This is because of the substantial mass of the oscillatingparts. These high bearing pressures mean high friction losses and,hence, inefcient use of the energy available. By providing the energystorage means -of the present invention associated with the oscillatingcutter shaft, the friction losses due to high bearing pressures aregreatly reduced. For example, upon deceleration the kinetic energy, byvirtue of the momentum of the mass of the oscillating system, will bestored in the energy storage means whereupon it is immediately availableto accelerate the mass at the time the direction of movement isreversed. Thus, less torque is required from the prime mover and,consequently, lower bearing pressures are involved at the crank pins 44and 63. in other words, with the present invention more uniform bearingpressures throughout the operating stroke of the oscillating mass occur,and a more constant load is applied to the prime mover resulting inhigher efficiency and, hence, less power consumption. If one assumedthat the oscillating cutting mechanism had Zero mass, then the use ofthe energy storage means in accordance with the present invention wouldbe undesirable since it would merely increase the load on the primemover and provide no benefits. Of course, since all oscillatingmechanical systems involve substantial mass, the desirable features ofthe present invention result.

As was pointed out above, the theoretical ideal condition would be tohave the energy storage means tuned to the frequency of oscillationproduced by the prime mover. It has been found, however, that thisrequires energy storage means of such stiffness that a practical primemover would not be able to produce sufficient torque to initiateoscillation of the system. For this reason the natural frequency of theenergy storage means is tuned to a frequency lower than the frequency ofoscillation of the oscillating cutter mechanism.

While there have been illustrated or described several embodiments ofthe present invention, it should be understood that numerous changes andmodifications will occur to those skilled in the art, and it is intendedby the appended claims to cover all those changes and modificationswhich fall within the true spirit and scope of the present invention.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

l. In combination, an electric motor comprising a rotating shaft, anoscillating cutting means including a cutter shaft disposed in spacedparallel relationship with respectl to said motor shaft, meansinterconnecting said shafts to convert rotary motion of said motor shaftto oscillating motion of said cutter shaft, and resilient means securedto said cutter shaft, said resilient means being stressed in torsionfirst in one direction and then in the other upon oscillation of saidcutter shaft.

2. An electric shaver comprising a housing, an electric motor including.a rotatable shaft mounted in said housing, an oscillating c'uttingmeans supported in said housing including an oscillating cutter shaftdisposed in spaced parallel relationship with respect to said motor cshaft, means interconnecting said shafts to convert rotary motion ofsaid motor shaft to oscillating motion of said cutter shaft, andresilient means encompassing and firmly secured to the ends of saidcutter shaft, said resilient means being held in fixed position in saidhousing and stressed in torsion upon oscillation of said cutter shaft.

3. An electric shaver comprising a housing, an electric motor includinga rotatable shaft mounted in said housing, an oscillating cutting meanssupported in said housing including an oscillating cutter shaft disposedin spaced parallel relationship with respect to Said motor shaft, meansinterconnecting said shafts to convert rotary motion of said motor shaftto oscillating motion of said cutter shaft, a first rectangular block ofrubber bonded to one end of said cutter shaft, a second rectangularblock'of rubber bonded to the other end of said cutter shaft, means forclamping said blocks of rubber in stationary position in said housingwhereby oscillation of said cutter shaft causes said blocks of rubber tobe stressed in torsion, said rubber blocks storing energy from saidprime mover when said cutter shaft is moved toward the extreme ends ofits oscillating stroke and returning energy to said oscillating cuttingmeans when said cutter shaft is moved away from the extreme ends of itsoscillating stroke.

Ll. An electric shaver comprising a housing, an electric motor includinga rotatable shaft mounted in said housing, an oscillating cuttermechanism supported in said housing including an oscillating cuttershaft disposed in spaced parallel relationship with respect to saidmotor shaft, means interconnecting said shafts to convert rotary motionof said motor shaft to oscillating motion of said cutter shaft, a firstrectangular block of rubber bonded to one end of said cutter shaft, asecond rectangular block of rubber bonded to the other end of saidcutter shaft, means in said housing defining opposed V-shaped groovesfor clamping said blocks of rubber in stationary position in saidhousing when said housing is fully assembled whereby oscillation of saidcutter shaft causes said blocks of rubber to be stressed in torsion,said rubber blocks storing energy from said prime mover when said cuttermechanism is moved toward the extreme ends of its oscillating stroke andreturning energy to said cutter mechanism when said cutter mechanism ismoved away from the extreme ends of its oscillating stroke, said storedenergy overcoming the inertia of said cutter mechanism as it reversesits direction of movement.

References Cited by the Examiner UNITED STATES PATENTS 891,788 6/08Winans 7442 968,729 8/10 Baney 310-20 1,051,923 2/ 13 Sim 74--422,237,575 4/41 Quartullo 267-57.l X 2,238,435 4/41 Perry 287--522,549,561 4/51 Baker 74-42 2,688,184 9/54 lepson 30-43.9 2,719,711 10/55 Nallinger 267-20 2,726,445 12/55 Winther 30-43.9 2,903,789 9/59Schleifer 30-43.9 3,058,361 10/62 Freeborn 74-50 X WLLIAM FELDMAN,Primary Examiner.

MIRON C. KRUSE, Examiner.

1. IN COMBINATION, AN ELECTRIC MOTOR COMPRISING A ROTATING SHAFT, ANOSCILLATING CUTTING MEANS INCLUDING A CUTTER SHAFT DISPOSED IN SPACEDPARALLEL RELATIONSHIP WITH RESPECT TO SAID MOTOR SHAFT, MEANSINTERCONNECTING SAID SHAFT TO CONVERT ROTARY MOTION OF SAID MOTOR SHAFTTO OSCILLATING MOTION OF SAID CUTTER SHAFT, AND RESILIENT MEANS SECUREDTO SAID CUTTER SHAFT, SAID RESILIENT MEANS BEING